This Is The Internet

The internet isn't only on your screen. Or behind your couch. Or in Google's data centres. It's also underwater, where fibre-optic cables stretch across oceans and loop around continents.

Satellites are like dial-up. Nobody uses them. Undersea cables make the Internet global, with the most sophisticated of them capable of transmitting nearly 10 terabits of data per second, compressed through just a handful of fibre-optic strands. There are only hundreds of these cables in waters around the world. And they are all preposterously proportioned, as thin as a garden hose and as long as -- actually, nothing. No human construction matches them. They are the longest tubes ever made, and, for the first time ever, there's a truly accurate online map of them.

But only to a point. Telegeography has limited how far you can zoom in on the map, keeping the exact locations secret. But is even that much information dangerous? Telegeography's Stephan Beckert doesn't think so. "It's actually more dangerous to not know where the fibre is, because it makes it harder to plan redundancy in networks," he says. For a big network buying wholesale bandwidth across the pond-say a Facebook, Microsoft, or Citibank-the map is an essential tool. For the first time ever, we get to ogle the actual cables that carry the Internet, on the Internet.

Andrew Blum (@ajblum) is the author of Tubes: A Journey to the Center of the Internet, coming soon.